An autoimmune disorder that occurs when the immune system mistakenly attacks parts of the nervous system (in most cases, it affects the eyes) is called neuromyelitis optica (NMO). However, NMO may also affect the spinal cord and parts of the brainstem. Moreover, there are some treatments that may help reduce the frequency of attacks.
In other words, a rare chronic (long-term) disorder that negatively affects the eyesight and ability to move is called neuromyelitis optica. This condition is also known as Devic’s disease. In general, the full name of this disorder is neuromyelitis optica spectrum disorder (NMOSD). Previously, healthcare providers thought neuromyelitis optica was a rare form of multiple sclerosis (MS), but it is not.
This condition occurs quite rarely, and it affects about 2-3 people in every 100,000 people worldwide. Moreover, there are approximately 24,000 people with diagnosed neuromyelitis optica in the whole world.
How Does Neuromyelitis Optica Affect My Body?
To understand how this disorder affects you, we should know a little about how the nervous system works. This structure in the body consists of the brain and spinal cord (including the optic nerves that allow you to see). They form the central nervous system, which has a network of nerves that branch outward throughout the body. All nerves below the head are called the peripheral nervous system. Normally, the communication between the brain and nerves of the rest of the body occurs through chemical and electrical signals.
Furthermore, these signals travel through neurons that have arm-like extensions called axons. These axons carry the electrical signals to the synapses at the end of the axon. Therefore, these electrical signals in the neuron become chemical signals. Each axon has a protective layer called myelin. It is made up of fatty chemical compounds, and it helps prevent damage to the nerves. However, in people with neuromyelitis optica, this protective layer is damaged, which makes the axon vulnerable to damage and deterioration. In people with this disorder, damage often occurs in the optic nerve and spinal cord.
Symptoms
The symptoms of this condition often come and go. In some cases, an attack of this disorder can last up to a few months. Moreover, these attacks can be severe and cause permanent damage. Healthcare professionals have divided the symptoms of this condition into 3 categories. For example:
- Optic neuritis – These symptoms occur due to inflammation of one or both optic nerves.
- Myelitis – In such cases, inflammation occurs in the spinal cord.
- Brain function disruptions – It occurs when NMO affects the brainstem or hypothalamus, which control multiple automatic processes in the body.
Optic Neuritis
In normal circumstances, the eyes pick up light from the world around you and send signals through the optic nerve to the brain. Thus, the brain processes these signals and gives you a sense of sight. However, in people with neuromyelitis optica, the optic nerve becomes inflamed. Thus, swelling puts extra pressure on this nerve because there is not much space in that area of the head. The symptoms of optic neuritis can affect either one or both eyes. Check some symptoms below:
- Blurred vision (this symptom often worsens with physical activity)
- Eye pain
- Partial vision loss or blindness – In some cases, people with neuromyelitis optica may lose their vision in one eye. For instance, loss of the center of the field of vision.
- Difficulty seeing in low light
Myelitis
In such cases, inflammation occurs in the spinal cord, which puts pressure on it and nearby nerves. Sometimes, it may block nerve signals completely (transverse myelitis). Check some symptoms below:
- Muscle weakness or paralysis – These symptoms occur when the swelling affects the spinal nerves, causing problems using your arms and hands or walking or standing issues. When myelitis occurs in the cervical spinal cord, you may experience paralysis or weakness in the muscles that control breathing, which is life-threatening.
- Spasticity – It occurs when a lack of control signals from the brain causes the muscles to act on their own. As a result, the muscles tighten uncontrollably.
- Pain – This symptom occurs due to pressure on the spinal cord.
- Incontinence – Sometimes, myelitis may affect the nerves that control the bladder and bowels, which often leads to urinary or bowel incontinence.
- Sexual dysfunction – This condition may also negatively affect the signals that control sexual functions in the body.
Brain Function Disruptions
While commonly, changes in the brain occur in people with multiple sclerosis, sometimes, NMO may cause these changes. This disorder may impact the hypothalamus and brainstem, causing serious health problems. The brainstem is the lower part of the brain (at the lower back of the skull). It controls autonomic processes in the body, including blood pressure, heart rate, breathing, and others. When problems in the brainstem occur, it may lead to changes in these processes. Check some symptoms below:
- Uncontrollable hiccups or itching (also known as pruritus)
- Nausea
- Vomiting
- Hearing loss (deafness)
- Diplopia (double vision)
- Nystagmus (uncontrollable eye movements)
- Facial paralysis
- Dizziness
- Ataxia (problems with coordination and balance)
- Trigeminal neuralgia (nerve pain that people feel in their face)
Some people with NMO may also have narcolepsy symptoms, such as excessive daytime sleepiness.
Causes
Healthcare providers can explain this condition partly. They suspect immune system problems and other autoimmune or inflammatory disorders play a role.
Immune System Malfunctions
Doctors have identified two forms of NMO. For example:
- Aquaporin-4 (AQP4) antibodies – This is a protein on the surface of some nervous system cells that moves water in and out of cells. AQP4 antibodies mistakenly tell the immune system to attack this protein, causing damage to the nerve cells in people with NMO. Approximately 80% of people with this autoimmune disorder have AQP4 antibodies in their blood.
- Myelin oligodendrocyte glycoprotein (MOG) antibodies – This is another protein in the blood that helps keep the myelin coating on neurons. However, MOG antibodies mistakenly tell the immune system to attack this protein, causing damage to the protective layer of the nerves. About 6.5% of people with NMO have this antibody in their blood.
Currently, doctors do not fully understand why these malfunctions of the immune system occur. Some research has shown that sometimes these malfunctions appear after an infection. About 15% to 35% of people with NMO had some type of infection before this autoimmune condition.
Moreover, NMO may occur in some people who do not have AQP4 or MOG antibodies in the blood. About 13.5% of people with NMO do not have these antibodies. In this case, the condition is called idiopathic neuromyelitis optica. Additionally, some healthcare providers believe that NMO that involves MOG antibodies is a separate disease, but more research is needed to confirm this.
Other Autoimmune or Inflammatory Disorders
NMO may occur on its own, but it is more likely to happen in people with other inflammatory or autoimmune diseases. Some of them are listed below:
- Celiac disease
- Systemic lupus erythematosus (lupus)
- Sarcoidosis
- Sjogren’s syndrome
- Antiphospholipid syndrome
- Myasthenia gravis
Genetics
Some experts suspect that genetics could play a role in NMO. They suspect this because it occurs more commonly in certain ethnicities or racial backgrounds, and about 3% of NMO cases involve people of the same family.
In addition, it is not possible to prevent or reduce the risk of developing NMO because healthcare professionals do not fully understand what causes it.
Diagnosis
Another difference between multiple sclerosis (MS) and NMO is in some test methods that can confirm that a person has it. Usually, doctors use a combination of the following tests and procedures to confirm NMO. For example:
- Blood tests – These tests are done to check for the APQ4 and MOG antibodies that are often found in people with NMO.
- Neurological and physical examinations – During these procedures, doctors will check for abnormalities linked to the disease. They may also check your senses, including reflexes, muscle movements, balance, and facial functions.
- Personal and family history – Doctors often evaluate your and your family’s history to get more clues about the disease.
Treatment
Unfortunately, it is not possible to cure this condition. That’s why the treatment focuses on relieving the symptoms, preventing life-threatening complications, and improving your quality of life. In general, the treatment for this autoimmune disorder takes 2 forms. For example:
- Acute treatment – It involves Corticosteroids to relieve inflammation that may cause permanent damage even in the early stages of the disease.
- Long-term treatment – This type often involves medicines that suppress your immune system, which mistakenly attacks healthy cells. Usually, people should take these medications for the rest of their lives.
Medicines and Treatments
In most cases, doctors recommend the following treatments for people with NMO. These include:
- Anti-inflammatory medications – While most of the time, doctors prescribe Prednisone (a corticosteroid) to reduce inflammation of the nervous system, in more severe cases, people may need IV (intravenous) medicines to reduce swelling (inflammation). These IV medicines are often given to patients in the hospital.
- Plasmapheresis (also known as plasma exchange) – When steroids do not work, doctors may recommend a plasma exchange. It involves the removal of blood plasma from your body and replacing it with a matching amount of donor plasma. It may help reduce the immune system’s response and inflammation.
- Intravenous immunoglobulin (IVIG) – This treatment is often recommended by doctors to reduce the response of the immune system.
- Immune-suppressing medicines (also called immunosuppressants) – This group of medications is used to suppress the immune system activity that attacks healthy cells in the body. Commonly, people with NMO should take these medicines for the rest of their lives.
Treatment Adverse Reactions
Some of the NMO treatments may cause some adverse reactions (especially immunosuppressants). While the immune system attacks healthy cells in the body, it also protects it from bacteria, viruses, and other germs that can make you ill. When you administer immunosuppressants, the immune system is no longer able to fight these germs, which increases the risk of developing the following infectious diseases. These include COVID-19, influenza (flu), pneumonia, and others.
Frequently Asked Questions
Who Does Neuromyelitis Optica Affect?
While it is not possible to determine the exact cause of NMO, doctors have identified some factors that put you at increased risk of developing it. Examples include:
- Sex – This condition occurs in women more frequently than in men.
- Age – Most diagnosed cases are in people between the ages of 30 and 40.
- Race – According to some research, NMO occurs more frequently in specific races. One example is people of African descent (especially African Caribbean descent).
Can neuromyelitis optica spread from person to person?
Nowadays, there is no evidence that NMOSD (NMO) can spread from one person to another.
How soon after treatment will I feel better?
Usually, you may notice the first improvements within a few days or weeks after starting the treatment. However, the recovery time varies among people because it depends on several factors. If you have any other questions, ask your healthcare provider.
